The force of kinetic friction acts in the oppose of the moving object. An object of mass m moving at velocity v has a kinetic energy equal to ½mv 2. Other units for energy include the newton-meter Nm and the kilogram meter squared over seconds squared kg m 2 s 2.
When I say the energy of motion I am strictly referring to the kinetic energy of the system.
The force of kinetic friction acts in the oppose of the moving object. Translational kinetic energy of a body is equal to one-half the product of its mass m and the square of its velocity v or 12mv2. By definition mechanical energy is the sum of the kinetic and potential energy of a system. The first term ɣmc 2 is known as the total energy E of the particle because it equals the rest energy plus the kinetic energy.